(((((Anony)))))
I'm sorry to hear about your sister leaving

I know how it hurts when a loved one leaves you ..... but atleast you know that she will be back! She is still in your life and most especially in your heart. Right now it is really tough, but i promise it will get easier, and you can do this. Talk with your mom, be each others support system, i'm sure she needs you just as much as you need her right now.
Hope you are feeling better